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Angular 2 – The future of component based JavaScript Frameworks

27 December 2016

WRITTEN BY GARETH DUNNE @JSDIARIES

What is Angular 2?

Angular 2 is the latest in the growing trend of JavaScript frameworks for creating web applications. It is not an MVC framework but rather a component based framework that has been completely re hauled and revived from Angular 1. The key differences between Angular 1 and 2 are that Angular 2 is built with mobile support, heavy use of TypeScript and the $scope to glue the view and controller has now beentotally removed.

The fact that Angular 2 is mobile-orientated allows Truly Native Mobile Apps to be built with technologies usch as NativeScript or Ionic.

Am I ready to learn it?

If you are eager to learn Angular 2 and have no previous experience with Angular 1 you are in luck! These frameworks differ greatly from each other so don’t be afraid to delve straight into it. There are, of course some prerequisite knowledge that I would recommend to have.

Backend

In order to create a practical application that would simulate one already in production, it is recommended to use a database instead of simulating data. You could use Node.js and MongoDB to accomplish this. By having a backend set up and ready to interact with you are enabling yourself to work on a application that is “true to life” or so to speak.

This isn’t totally necessary if you want to play around with Angular and create an application quickly. However, you will have to do this at some point as the scope of your application gets more complex so its best to establish what you will use at the beginning.

JavaScript

A good grasp of JavaScript fundamentals will obviously put you in a good position for starting an Angular 2 application. However, the real benefit of this is for the inevitable debugging sessions you will have to endure. In this case, knowing Vanilla JavaScript is extremely beneficial as the ability to trace and understand errors from the compiled TypeScript will allow you to solve problems much quicker.

Wes Bos builds 30 practical JavaScript things and with some latest ES6 practices. All these small applications built contain no additional frameworks or boiler plate code and they really indicate how much you can do without other libraries. Extremely useful down the line when debugging/implementing an Angular 2 application.

TypeScript

And who can forgot the beautiful TypeScript. Ah, bread and butter of an Angular 2 application. TypeScript is a superset of JavaScript and it allows you to write JavaScript in a class based or object oriented style. This code is then compiled to clean JavaScript output. This is why its important to know pure JS for debugging. Its hard to find a better introduction to TypeScript than this video by .NET Interview Preparation Videos

Similarly, if you were trying to find a more cohesive way to learn the basics of Angular 2 + TypeScript I would highly recommend checking this Angular 2 development book below by Yakov Fain.

If you have ever used a Modal-View-Controller or MV* system, then you will know the importance of separation of concerns . This basically means dividing your application’s business logic, data and visual markup into separate sections that are easy to navigate . Angular 2 uses a component based architecture that would be comparable but not identical to this.

To create an Angular 2 component in your project directory run the command

ng g component my-new-component

or

ng g c my-new-component

You will now have folder called my-new-component or whatever name you specified.

Generating New Angular 2 Component

This folder containers the relevant typescript and styles files created in this folder. In order for us to link this new component into our app component we have to specify it in app.module.ts directives array in the @Component meta-data. We then need to put the selector of our new components into the first-apps template property in its meta data section.

App-Module Component Declaration

Getting Started

Angular CLI

In order to use npm to download the Angular CLI package and install it globally on our local machine we need to install the latest version of Node.js .

Your project will be created in your specified directory. It takes all configuration and prerequisite steps such as:

Creating our app files

Configuring TypeScript and Typings

Adding script tags for

Angular2

Rx.js

System.js

Configuring System.js

Creating our Angular 2 component

Using the command line interface we must also install TypeScript globally on our local machine.

install -g typescript

We will use typescript as a subset of JavaScript in order to the define the type of member variables and class method parameters used in our application. TypeScript supports new ECMAScript standards and compiles them to older targets of your choosing (such as ES3 or ES5 . This means that you can use features of ES2015 and forthcoming versions with our Angular 2 application.

Other Versions?

So something to really try and get your head around are these will new Angular versions. Google has stated that all forthcoming Angular versions will be backwards compatible with Angular 2. Will Angular 2 be irrelevant in 6 months because of forthcoming versions in Angular 3 and 4? Well this depends. Angular 4 is the next major version released, not 3. The difference between Angular 2 and 3 will not be another full core change. These new versions will now be subsequently released twice a year. So with this backwards compatibility in theory, no version will be get left deprecated from Angular 2 but we’ll just have to see how this pans out.

So while these incremented versions do cause some differences in the architecture itself. What are we supposed to call Angular as its base name if it keeps getting incremented every 6 months? This is an ongoing discussion in r/Angular2